Needle bar mounting for zigzag sewing machines



Oct. 16, 1962 H. J. GoosMAN NEEDLE BAR MOUNTING FOR ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 2 Sheets-Sheet 1 NN mm vm wm INVENTOR. HERBERT J. Goos/WAN WITNESS TToRNW Oct. 16, 1962 H. J. GoosMAN NEEDLE BAR MOUNTING FOR ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 2 Sheets-Sheet 2 28 1N VEN TOR.

HERBERT J. GoosMA/v 25 Fig. 2.

` WITNESS ATTORNEY 3,058,436 NEEDLE BAR MOUNTENG FOR ZIGZAG SEWING MACHlNES Herbert J. Goosman, Watclaung, NJ., assigner to The Singer Manufacturing Company, Elizabeth, NJ., a corporation of N ew Jersey Filed Jan. 25, 1960, Ser. No. 4,493 3 Claims. (Cl. 112-158) The present invention relates to zigzag sewing machines and has for a primary object to provide in a zigzag sewing machine means for mounting the needle bar for lateral vibration, which means will provide for positioning of the needle relatively to the loop taker to insure loop seizure at the various lateral positions of the needle, and which means is simple and economical for reducing manufacturing expense and is also dependable and durable.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

FIG. 1 is a vertical sectional view longitudinally of a sewing machine embodying the present invention,

FIG. 2 is a sectional view taken substantially on the line 2-2 of FIG. l, and

FIG. 3 is a fragmentary detail sectional view of the needle bar mounting.

The present invention is herein disclosed as embodied in the sewing machine forming the subject matter of the copending United States patent application of Johnson et al., Serial No. 4,430, iiled January 25, 1960, wherein the machine is fully illustrated and described and to which reference may be had for a more complete understanding of the machine.

With reference to the drawings, there is illustrated a sewing machine having a frame consisting of the bed 1, standard 2 rising from one end of the bed and carrying a bracket arm 3 that terminates in a head 4 overhanging the bed. Iournaled longitudinally of the bracket arm 3 is a main shaft 5 which is driven from a motor 6 by a belt 7.

Mounted in the head 4 is a needle bar 8 having a needle 9 secured on the lower end thereof by a needle clamp 10. Endwise reciprocation is imparted to the needle bar 8 by a crank 11 on `the head end of the main shaft that is connected by a link 12 to a collar 13 on the needle bar. The top of the bed 1 is formed as a work supporting bed plate 1'4, which, beneath `the head 4, has a throat plate 15. Upon endwise reciprocation vf the needle bar 8, the needle 9 penetrates the throat plate to define the point of stitch formation thereon, and, beneath the throat plate 15, cooperates with a loop taker, indicated generally at 16, in the formation of lock stitches.

The loop taker 16 is preferably a vertical axis oscillating hook disposed in front of the needle bar and comprises a hook body 17 formed with a loop seizing beak 18 and having a shaft 19 journaled in a bracket 20 integral with and depending from the bed plate 14. Oscillation is imparted to Ithe hook 17 by a rotary vertical axis shaft 21 journaled in the standard 2 and gear connected at its upper end to the main shaft 5 and having a crank 22 mounted on the lower end thereof. The crank Z2 is connected by a link 23 to one arm 24 of a bell crank lever pivotally mounted by a screw 25 on the bracket and having a second arm 26 connected by a link 27 refr t to a crank arm 28 secured on the lower end of the hook shaft 19.

Work is fed past the point of stitch formation by a feeding mechanism which denes the line of feed of the machine. The feeding mechanism comprises a feed bar 29 pivotally mounted at one end on an upstanding crank arm 30 on a feed advance shaft 31 which is oscillated in the usual manner by a pitman 32 cooperating with an eccentric 33 on the main shaft 5. Feed lift motions are imparted to the feed bar 29 by a feed lift shaft 34 having at one end a crank arm 35 connected by a link 36 to the feed bar and at the other end a crank arm 37 carrying a cam follower 38 that tracks an axial displacement cam surface 39 formed upon the top of the crank 22, the mechanism being biased by a compression spring 40 acting between the crank arm 35 and the bed plate 14. The feed bar 29 carriers a feed dog 41 that engages the work through slots in the throat plate 15. The work is held down against the throat plate 15 and the feed dog 41 by a presser foot 42 secured upon the lower end of a presser bar 43 that is mounted in the head 4 and biased downwardly by a spring 44.

To provide for lateral vibration of the needle bar 8 to effect a zigzag or ornamental stitch, there is provided a swinging needle bar gate 45 having spaced bearing lugs 46 in which lthe needle bar 8 is mounted for endwise reciprocation. The needle bar gate '45 also includes a pair of spaced bearing lugs 47 Ipivotally mounted on an intermediate portion 48 of a pivot rod 49 secured in spaced upper and lower bosses 50 and 51 in the head 4. In addition to the intermediate portion 48, the pivot rod 49 also includes a head 52 at its lower end that is received within a bore 53 in the boss 51 and secured therein by a set screw 54, and a reduced end portion 55 at its upper end that is received within a bore 56 in the boss 50 by a set screw 57. A collar 58 is secured by a set screw 59 on the intermediate portion 48 of the pivot rod 49, and together with the head 52, holds the needle bar gate against end play on the pivot rod 49.

Upon pivotal movement of the needle bar gate 45 about the axis of -the intermediate portion 48 of the pivot rod 49, the needle bar 8 is moved laterally relatively to the line of feed so that upon alternate `stitches it may penetrate the work at different positions, thereby defining a zigzag or ornamental stitch pattern. Regardless of the lateral position of the needle, it must, of course, be in a position to cooperate with the loop seizing beak 18 upon each stitch; that is, it must present a loop of needle thread for seizure by the beak 18. To insure loop seizure upon each stitch, the needle bar gate is pivotally mounted for oscillation about an axis that is aligned with the axis of oscillation of the hook 17 which defines the axis of the arcuately moving loop seizing beak 18 so that upon oscillation of the needle bar 8, it will always descend at a point a fixed distance from the path of movement of the loop seizing beak 18 of the hook 17. Accordingly, the intermediate portion 48 of the rod 49, which defines the axis of oscillation of the needle bar gate l45, is substantially aligned with the hook shaft 19 which defines the axis of oscillation of the hook 17.

To reduce manufacturing tolerances and thereby reduce the manufacturing expense of the machine, there is provided an adjustment for effecting alignment of the intermediate portion 48 of the pivot rod 49 with the hook shaft 19. For ythis purpose, the intermediate portion 48 of the pivot rod 49 is made eccentric relatively to the head 52 and the reduced end portion 55, the head 52 and the reduced end portion 55 being co-axial. Upon turning of the pivot rod, which is rfacilitated by a screw driver slot 60 in the bottom of the head 52, the intermediate portion 48 in shifted bodily Ithereby shifting the pivot axis of the needle bar gate 45 into alignment 3 with the axis of the hook shaft 19. When this adjustment is once etected, the set screws 5-4 and 57 are turned down to lock the pivot rod 49 in the adjusted position.

In the disclosed machine oscillation is imparted to the needle bar gate 4S by means of a pitman 61 arranged longitudinally of the bracket arm 3 and pivotally connected at the head end thereof to the needle bar gate by means of a bracket 62 pivotally mounted on a stud 63 secured in the needle bar gate 45. The connection between the pitman 61 and the bracket 62 comprises a screw 64 extending loosely through a slot 65 in the bracket 62 and threaded into the pitrnan 61, thus providing an adjustment for centering the needle 9 in the range of lateral vibration.

For imparting endwise movement to the pitman 61 and thereby oscillating the needle bar gate 4S, the end of the pitman 61 extends loosely through a slot in the bottom of a plate 66 pivotally mounted in 4the bracket arm 3 on a pivot pin 67. On the side of the plate 66 from the needle bar 8, the pitman 61 has a block 68 that is adapted to abut against the adjacent face of lthe plate 66. A cam follower 69 is connected to the plate 66 and has a follower element 70* that tracks an ornamental stitch pattern cam 71 releaseably clamped by a screw 72 on the upper end of a tubular cam shaft 73 that is journaled upon a stud 74. Rotation is imparted to the cam shaft 73 by a worm wheel 75 meshing with a worm 76 on the main shaft 5. A torsion spring 77 is coiled about the intermediate portion 48 of the pivot rod 49 between the collar 5S and the upper bearing lug 47. The lower end of the spring 77 yis anchored tok the collar 58 and the upper end is behind the needle bar gate 45, thus biasing the same pivotally about its pivot axis and, through the pitman 61 and plate 66 to hold the follower element 70 in `tracking engagement with the cam 71.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modiications which do not depart trom the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus described the nature of the invention, what I claim herein is:

1. In a zigzag sewing machine having a frame including a bed and a head overhanging said bed, a lock stitch P loop taker journaled in said bed for angular movement about an axis intersecting said head and having a loop seizing beak movable in an arc about said axis, a pivot rod mounted in said head for angular adjustment on an axis substantially aligned with the axis of said loop taker, said pivot rod having an eccentric portion formed on an axis parallel to and spaced from the axis of said pivot rod, a needle bar gate mounted on said eccentric portion of said pivot rod for oscillation about the axis thereof, a needle bar mounted in said needle bar gate for endwise movement along an axis parallel to the axis of said eccentric portion and spaced therefrom to position the same in loop seizing cooperation with said loop seizing beak, and means for securing said pivot rod in angularly adjusted position in said head to elfect an adjustment of the axis of said eccentric portion of said rod into alignment with the axis of said loop taker.

2. In a zigzag sewing machine Ihaving a frame including a bed and a head overhanging said bed, a lock stitch loop taker journaled in said bed for angular movement about an axis intersecting said head and having a loop seizing beak movable in an arc about said axis, a pivot rod mounted in Said head for angular adjustment on an axis substantially parallel to the axis of said loop taker, said pivot rod having an eccentric portion formed on an axis parallel to and spaced from the axis of said pivot rod, a needle bar gate mounted on said eccentric portion of said pivot for oscillation about the axis thereof, a needle bar mounted in said needle bar gate for endwise movement along an axis parallel to the axis of said eccentric portion and spaced therefrom to position the same in loop seizing cooperation with said loop seizing beak, and means for securing said pivot rod in angularly adjusted position in said head to eifect an adjustment of the axis of said eccentric portion of said rod.

3. In a zigzag sewing machine having a frame including a bed and a head overhanging said bed, a lock stitch loop taker journaled in said bed for angular movement about an axis intersecting said head and having a loop seizing beak movable in an arc about said axis, a pivot rod having a head and an end portion co-axial therewith at the end opposite therefrom and an eccentric intermediate portion formed on an axis parallel to and spaced from the axis of said pivot rod, means for mounting the head and the end portion of said pivot rod in the head of said frame on an axis substantially aligned with the axis of Said loop taker and for angular adjustment about said axis, a needle bar gate mounted on said eccentric portion of said pivot rod for oscillation about the axis thereof, a needle bar mounted in said needle bar gate for endwise movementl along an axis parallel to the axis of said eccentric portion and spaced therefrom to position the same in loop seizing cooperation with said loop seizing beak, and means for securing said pivot rod in angularly adjusted position in said head to effect an adjustment of the axis of said eccentric portion of said rod into alignment with the axis of said loop taker.

References Cited in the le of this patent UNITED STATES PATENTS 1,466,154 Sharf Aug. 28, 1923 1,981,504 Goodwin Nov. 20, 1934 2,600,543 Karlsson June 17, 1952 2,653,557 Casas-Robert et al Sept. 29, 1953 2,667,133 Court Jan. 26, 1954 2,757,626 Fujita Aug. 7, 1956 2,873,707 Engel et al. Feb. 17, 1959 

